Age-related effects of clear-cut–old forest edges on bird communities in Lithuania

Abstract

The influence of forestry-induced edges on plant and animal communities is dynamic in time, a fact that has been overlooked in many studies on the edge effect. This study assessed age-related changes in edge effects on breeding forest birds after clear-cutting in mixed deciduous old forest in south-west Lithuania. In total, 182 transects starting at the edge and extending 200 m into the forest were visited twice during the breeding season. The mean abundance of birds was higher in the 10 m wide zone closest to the edge than farther inside the forest (10–200 m from the edge) and increased in this 10 m wide zone from young edges (1–3 years) to middle-aged (4–9 years) and old (10–20 years) edges. The edge influence on the structure of forest bird communities penetrated deeper and deeper into the forest during the first 20 years after clear-cutting: young edges were characterized by a 50 m wide zone of influence into the forest, middle-aged edges by a 90 m wide zone and old edges by a 120 m wide zone. Based on changes in bird community patterns along transects penetrating into the forest, four zones were distinguished: the edge contact zone, the main edge zone, the intermediate zone and the forest interior zone.